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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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quote:
Originally posted by marto:
Well to be honest I have no way of testing the TZ85as @ 85A which is there "Hobby" continuous rating. I would say ~50A cont is more realistic but to be honest I really don't know.
Easy Way = Take a couple of sacrificial units and pop your head into an auto electrician shop (a real one that rebuilds alternators and things, not a general purpose auto repair where they just replace them), and ask them to throw your ESC on the alternator load testing machine - (bring suitable wiring and a few units of universal Australian currency (beer) or offer to pay them to make some smoke.).
They have an adjustable current sink (usually a carbon disk pile) that will suck up a few hundred amps (briefly) that will reveal the ESC's *real* amps capabilitity (as opposed to the hobby amps rating as mis-read by the marketing department).
We borrowed Gary Stotts (he has one) during development testing and found the IBC would easily take short bursts (<5 seconds) of around 90-100 amps on one channel, and took one or two *Really* short (<1 second) bursts of 120 amps. On the 3rd ~120amp burst, one of the 1405 Mosfets exploded (well, actually shot out a really cool looking 0.5cm jet of flame)
We also learned about the low-temp (cream coloured and common ) vs high-temp (white colored and rare) TO220 insulator bushes using that method. 
If youre still tinkering with ESC's you might even be able to ask your autoelec where to pickup your own Carbon pile current sink, since they're pretty ancient tech these days and being replaced with automated-alternator testing units, so you probably want one of those scruffy-looking auto elecs with a pile of ancient looking gear down the back of the shop, not a swisho new one.
Option 2 = Hit the wrecking yard, and collect a bunch of headlights from something noone wants (Ask at the desk) and mount/wire/switch them on a board so you can throw the load up a bit higher with each set of extra headlights you enable. Then you can have your own current sink, light and room heater all at the same time ! (If you have the space).
*this is only a rough guide, since both methods typically simulate fairly linear loads, and dont apply all the EMF, kickback, commutator hash and so on that real coil wound motors do that result in the death of some of the the toughest esc's
I suppose you could also rig a starter motor with a brake contraption and more realistically load test them that way if you could be bothered.
_________________
Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Mon Sep 03, 2012 12:11 am |
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